Place a small sharp knife under the shiny membrane (called silverskin) of the tenderloin, and slide it along the membrane (away from you) to remove it. If needed, use a paper towel to better grip the silverskin.
If your pork tenderloin has any fatty bits, they can also be removed.
Prepare pork tenderloin as desired.
Notes
Use a sharp knife with a narrow blade.
Pat the meat dry before beginning and if necessary use a paper towel to obtain a firm grip.
Silverskin typically does not come off in one piece. Work slowly to slice the silverskin off into small pieces and discard.